Whether you’re moving into a new home, or your existing furnace or boiler is struggling with poor performance, knowing how old your HVAC equipment is can help you make cost-effective decisions between further maintenance or replacement.

Furnace age impacts energy efficiency, indoor air quality, and even the purchase price of a home.

Find the Age of Your Furnace by Serial Number 

Most HVAC manufacturers use the first four digits of the furnace, boiler, or AC unit to communicate the date it was made. While newer furnaces have the manufacture date noted conveniently on the side, older models can take a bit more digging.

Here’s how to find the serial number on your furnace:

  • Remove the small door on the front of your furnace. In some cases, there will be a sticker on the inside of the door with the manufacture date.
  • Turn off the furnace – we have steps for this – and look at the fan blades. Some manufacturers stamped the date on the fan.

Once you’ve found the serial number, examine the first four digits. For example, a furnace or boiler serial number that starts with 0188 was likely made in January 1988.

How Do I Know How Old My Furnace Is If I Can’t Find the Serial Number? 

No luck finding the serial number? You might also be able to determine the age of your furnace by the model number. Look for the model number in the same places that you’d expect to find the serial number above; in fact, some manufacturers may treat these numbers interchangeably.

  • You can find out the age of your furnace by looking at the nine-digit model number. The first digit will be a letter. The second and third numbers will be the year, and the fourth and fifth numbers denote the week of the year the unit was made.

If all else fails, contact the furnace manufacturer. They may be able to determine the model and approximate age by photos or other identification methods.

Related Content: What Is More Expensive, Heating or Cooling?

Does the Age of My Performance Affect Efficiency? 

How efficient is a 20-year-old furnace? Compared to modern units, older furnaces cost you more to operate. Newer EnergyStar-rated furnaces or electric air-exchange heat pumps, require less energy to maintain the same temperatures. Older systems operate at roughly 56-70% efficiency, with more modern furnaces being up to 98.5% efficient and heat pumps being 300% efficient.

While it may not make financial sense to replace an old furnace if the old unit is working, it should inform your decision to fix the unit when problems arise, including considerations like:

  • The cost of one-time or recurring repairs compared to heating system replacement
  • The expected energy savings from upgrading to an electric heating system or heat pump
  • The average lifespan of gas or electric heating systems
  • Seasonal needs, such as waiting to replace the unit until next fall when it will be needed

Make Smart HVAC Decisions with Professional Insight 

Your local One Hour Heating & Air Conditioning Comfort Specialists can help you decide when it’s time to replace your furnace and choose the best option for your home and your climate. We know that upgrading or replacing your heating system is a big financial decision.

Count on us to offer friendly, professional advice based on your situation. We’re always here to help! Request an appointment online or call (800) 893-3523 today.